Wheat, Milk (farm), oil, exports, maybe coal?
From a report I found circa 2015:
If these tax credits were granted to particular industries or specific companies, rather than a general tax credits for any American company, then I'm opposed. The only time I would consider it if it was a national defense contractor like let's say Lookheed who we depend on for certain systems that defend us militarily. However, even there, I would encourage as much competition as possible.